While taking off everything seemed normal until rotation. the pilot then noticed that the airplane's nose seemed heavy and slow to lift off. He lowered the nose to gain airspeed and rotated again to achieve only a "very flat fly out." About 100 feet above the ground he initiated a right turn to avoid power lines. As he rolled out he was at about 40 miles per hour on the airspeed indicator and he could not control the pitch with full aft stick. The airplane started to descend and impacted the ground in a hay field. Examination of the airplane revealed no preexisting anomalies. According to the airplane designer, best climb is attained at 65 knots and at 45 knots the elevator will feel mushy. The pilot and owner did not submit a NTSB Form 6120.1.